Linkwitz Orion and Phoenix speakers have interested me for quite some time. I'm inclined to think they are hard to beat in terms of fidelity. They are quite expensive to construct, however, considering that they use a considerable number of expensive drivers and require and require at least 6 amp channels. More recently I have come across what appears to be a viable alternative.

From my own experience, I have a 6.5" fullrange crossed to two cheap Vifa 10" woofers, active EQ, all run in dipole (with folded baffle probably closer to the Nao, i.e. slightly cardioid, but I have not measured them accurately enough to confirm). And I have heard the Orions.

The cheaper drivers give you less detail, and more distortion in the bass. Subjective slam and bass fullness is higher (due to higher distortion I guess). The smaller mid (or my fullrange) give you better imaging.

(JPK) I just joined this forum and was pleased to see that the NaO is being discussed here. FWIW, the NaO was designed to be a simpler system with similar capabilities as the Orion. The hybird approach of acitve eq and woofer/panel crossover combined with a passive mid/tweeter crossover allows the system to driver by only two amplifiers. The panel has similar max SPL capability as the Orion, but the U-frame woofer has significantly higher output capability than the dual 10" XLS woofer of the Orion, on the order of 10 dB greater max SPL. The woofer is not a perfect cardioid but does have reduced rear radiation to the tune of about 10 dB below the on axis response.

John, as an admirer of your work in the field of audio design and measurement I'd like to wish you the warmest of welcomes here. You will find there is much interest in the open baffle/dipole concept generally. Regarding the U-frame section in the NaO, an idea I find particularly interesting, could you give some idea as to how the pseudo-cardiod radiation pattern interacts with the room in comparison to dipoles? This is often mentioned as a large advantage with dipoles as room modes are comparatively unexcited compared to monopole sources. Also, would there be any benefit in 'de-tuning' the U-frame with an exponential (Karlsson- type) slot, as somebody suggested in another thread?